Modeling the Yellowstone magma plume with a vat of sugar water

Model mimics the complex volcanism of the Pacific Northwest.

If you're a fan of volcanoes—and really, who isn't?—you're probably aware of the Yellowstone supervolcano. The current caldera sits above a plume of magma that currently powers the national park's geysers and hot springs, but in the past has been the source of massive eruptions. And since the North American plate is drifting across the site of the mantle plume, each of these earlier eruptions took place further to the west of the one that came after it. By traveling west from Yellowstone, you can track eruptions backward in time.

It's a great story, but it's only true up to a point, and that point is somewhere near the Washington-Idaho border. That's where the eruptions that form the Snake River Plain (which ends at Yellowstone) give out, and the High Laval Plains begin. When that happens, the age progression reverses: suddenly, as you move west, the volcanoes get younger. Confusing matters further, just to the north there are even older deposits where the magma bursts out of the Earth in floods rather than through volcanoes. There have been several competing explanations for this, but now some researchers claim to have sorted it all out. Their tool? A small vat full of sugar water.

Tectonic events—things like volcanoes and Earthquakes—tend to occur rather suddenly. But the engines that power them, like plate movement and the rising of magma plumes, occur on a leisurely scale, often traveling just a few millimeters a year. That makes studying these sorts of processes rather challenging, since most researchers (and even fewer grant funding agencies) are not willing to engage in a project that takes millions of years to reach any conclusions.

To get past these challenges, an international research team set up a system that shrank down the vast time and space scales involved with tectonic processes. To do that, they needed something that behaved a bit like molten rock: dense enough to not flow quickly, but still able to respond to changes in density caused by heating. They settled on a tank full of a specific concentration of glucose, a simple sugar, dissolved in water. When everything was scaled properly, 20mm was the equivalent of 100km, and each minute of simulation was the equivalent of a year in the real world.

The Pacific Northwest is geologically complex. The North American plate is moving westward slowly, sliding over the Pacific plate and some other, smaller remnants of past plates. Meanwhile, the Pacific plate is sliding into the mantle where it melts once it gets sufficiently deep. (That melting powers the volcanoes of the Cascades, such as Mounts Shasta, St. Helens, and Rainier.) To simulate the Pacific plate's subduction, the authors sent a sheet of fiberglass into the glucose solution at a fixed angle. To capture the North American plate's westward drift, they rolled a mylar sheet slowly over the surface.

Finally, to make a mantle plume, they ran a hose to a specific point in the bottom of the tank. That hose injected a warm, pressurized glucose solution into the tank. This supply of glucose was marked with microscopic beads, allowing it to be tracked within the larger tank of solution.

The researchers found that when the plume finally reached the surface of their tank, representing the crust, it was concentrated in a single spot, which was much hotter than the surrounding liquid. This, they think, gave rise to the oldest volcanic features in the region, the Columbia River flood basalts. As the name implies, those formed from magma that flowed onto the Earth's surface in a large flood rather than a through a typical volcanic eruption.

Over time, however, the motion of the mylar sheet (representing the North American plate) caused the plume to split in two, with each of the halves moving in opposite directions. To the east, the plume narrowed and cooled, which the authors think accounts for the onset of the volcanism that produced the Snake River Plains and ultimately Yellowstone.

To the west, however, the diving Pacific plate drew in part of a plume and started sucking it downward, creating a bit of a vortex. Again, this caused the part closest to the surface to narrow and cool, which the authors say accounts for the production of the High Lava Plains.

If they're right, the whole thing has been nicely sorted out. Their model predicts various features of the motion of magma near the surface and more generally predicts that the base of the plume will actually be east of Yellowstone, but the whole thing gets dragged westward by the dynamics of the plate motion. Like all good models, this one has some predictive power, which will allow further testing.

In any case, it's pretty cool that so much can be visualized with a tank full of sugar water.

wait, if hotspot plume rises from the core-mantle boundary, how can you actually split it in the crust?

I'd guess it's some sort of shear effect?

If plate movement can split the mantle plume, why other plumes on the Earth weren't split? Like Hawaii? If anything, that one seems to move faster.

No doubt their experiment produced a plausible outcome, but there is really no way to be sure their experiment conditions mimic the chemical and physical conditions exactly like Earth interior. Especially, IF the plume does rise from core-mantle boundary (now thats an "IF" alright), their experimental may not be able to mimic that plume.

The 2012 book Oregon Geology describes the mechanism of the mantle plume breaking into separate pieces as it contacted the crust, just as described in the article, so this isn't a breaking discovery by any means. The authors are referencing others' work; they previously edited various editions of "Geology of Oregon." Some sections of the plume manifested themselves in the Columbia River Basalt Group, which now include the Steens Basalts, previously considered as separate from the CRBG. Another section gave rise to the volcanics of the Oregon High Lava Plains; yet another may be responsible for lavas in Nevada. The stem of the plume is what fired up the calderas of the Snake River Plain.

wait, if hotspot plume rises from the core-mantle boundary, how can you actually split it in the crust?

I'd guess it's some sort of shear effect?

If plate movement can split the mantle plume, why other plumes on the Earth weren't split? Like Hawaii? If anything, that one seems to move faster.

Hawaii is much further from a plate boundary isn't it?

It wouldn't be surprising that a plume encountering thin crust in the middle of a large ocean plate has very different behaviour from one in a more geologically complex environment under a continental plate with a nearby subduction zone.

Quote:

No doubt their experiment produced a plausible outcome, but there is really no way to be sure their experiment conditions mimic the chemical and physical conditions exactly like Earth interior. Especially, IF the plume does rise from core-mantle boundary (now thats an "IF" alright), their experimental may not be able to mimic that plume.

We know that the chemical and physical conditions aren't the same because the mantle is solid rock at high temperature rather than warm glucose solution. The model doesn't have to be that accurate to be useful and is really about demonstrating a possible mechanism that can hopefully be supported by further evidence from seismic surveys and further geology.

That makes studying these sorts of processes rather challenging, since most researchers (and even fewer grant funding agencies) are willing to engage in a project that takes millions of years to reach any conclusions.

This is pretty interesting research. The Yellowstone Volcano has the potential to severely disrupt life across the world, nevermind the catastrophic consequences for North America if it were to erupt in the same manner it has in the past (prevailing winds would spread massive amounts of ash over the midwest). Any science that gets us closer to understanding the volcano's mechanics is good.

" Like all good models, this one has some predictive power, which will allow further testing."

For which we just have to wait a few more millennia?

From the article:

Quote:

When everything was scaled properly, 20mm was the equivalent of 100km, and each minute of simulation was the equivalent of a year in the real world.

Well, maybe a few hundred thousand minutes before we see glucose erupt through the mylar sheet...

I think what they mean is predictions about the current state of the system. They are predictions because they are not yet observed, not predictions because they are about the future, per se. For example, "I believe if you look at Miss Scarlet's hands, you will find blood stains as well as some residue from the lead pipe."

That makes studying these sorts of processes rather challenging, since most researchers (and even fewer grant funding agencies) are willing to engage in a project that takes millions of years to reach any conclusions.

And since the North American plate is drifting across the site of the mantle plume, each of these earlier eruptions took place further to the west of the one that came after it. By traveling west from Yellowstone, you can track eruptions backward in time.

wait, if hotspot plume rises from the core-mantle boundary, how can you actually split it in the crust?

I'd guess it's some sort of shear effect?

If plate movement can split the mantle plume, why other plumes on the Earth weren't split? Like Hawaii? If anything, that one seems to move faster.

No doubt their experiment produced a plausible outcome, but there is really no way to be sure their experiment conditions mimic the chemical and physical conditions exactly like Earth interior. Especially, IF the plume does rise from core-mantle boundary (now thats an "IF" alright), their experimental may not be able to mimic that plume.

It's like any other model trying to mimic some natural event or system. It's a nice tool to help us maybe see things in another way which MAY help us see something we were missing but no one should expect these models to be an accurate representation of what is actually going on. I hate when the media and politicians do this and by doing so dumb down the general population.

And since the North American plate is drifting across the site of the mantle plume, each of these earlier eruptions took place further to the west of the one that came after it. By traveling west from Yellowstone, you can track eruptions backward in time.

Each eruption happened further east of the previous one.

Yes, that's what it says. Yours is probably a less confusing way to say it though.

I live right by Yellowstone NP, and all I gotta say is if that sucker blows during my lifetime, I'm glad I'll be at the heart of it. I'd hate to suffer the lingering effects, or die a slower death being farther away. It may not happen any time soon, but I have a feeling that when it does blow, humanity is pretty much done for.

I live right by Yellowstone NP, and all I gotta say is if that sucker blows during my lifetime, I'm glad I'll be at the heart of it. I'd hate to suffer the lingering effects, or die a slower death being farther away. It may not happen any time soon, but I have a feeling that when it does blow, humanity is pretty much done for.

Hard to say for sure, isn't it? Like you, I'd rather go out in the initial blast rather than stumbling through the post-apocalyptic land but there are possible scenarios that include increased activity in Yellowstone short of wiping out humanity.

The North American plate is moving westward slowly, sliding over the Pacific plate and some other, smaller remnants of past plates. Meanwhile, the Pacific plate is sliding into the mantle where it melts once it gets sufficiently deep.

The Pacific plate isn't subducting under North America until you get up to Alaska. The plate that's actually subducting under NA is the Juan de Fuca plate.

The Pacific plate has a strike-slip boundary with our continent, reaching the surface at the San Andreas fault system. Given a few tens of millions of years, LA will probably be smeared all across Anchorage.

The North American plate is moving westward slowly, sliding over the Pacific plate and some other, smaller remnants of past plates. Meanwhile, the Pacific plate is sliding into the mantle where it melts once it gets sufficiently deep.

The Pacific plate isn't subducting under North America until you get up to Alaska. The plate that's actually subducting under NA is the Juan de Fuca plate.

The Pacific plate has a strike-slip boundary with our continent, reaching the surface at the San Andreas fault system. Given a few tens of millions of years, LA will probably be smeared all across Anchorage.

Sorry, just a nitpick.

Hah! Finally, i successfully prepared for the Nitpick! Juan de Fuca is, i believe, the remnant of the Farallon plate, and it's what i was referring to in that sentence.

Given a few tens of millions of years, LA will probably be smeared all across Anchorage.

I thought North American Plate (or whatever plate that was) divert from Anchorage and now "we are" moving back up north/West? It must has a hell of fun for the plate to move down and then up again if that's what it was.

The Snake River volcanics peter out on the Oregon-Idaho border, not Washington. They start/end in a region on the border called the Owyhees, misnamed by the pioneers after Hawaii, which it resembles, but which they couldn't spell. If you've ever seen the dry side of Maui, it looks just like the basalt flows of the Owyhees.

The Yellowstone volcano erupted 2Mya, 1.2Mya, and 600Kya. The caldera is slowly rising and another eruption is likely in the next 100K years or so.

Missed this article when it was first posted, but the newer article on the Mt. Rainier subduction zone had a link at the bottom with the picture of Big Southern Butte (located in the eastern section of the Snake River Plain in southern Idaho), which I immediately recognized and had to click on. Lived for many years in Boise, and my job required me to drive weekly (sometimes several times a week) from Boise to Idaho Falls. The interstate was too boring so I usually drove State Highway 20 to 26 across the northern edge of the Snake River Plain. The drive from Arco to Idaho Falls passes right by Big Butte, and this and the other two large domes (seen in the pic) are the only features for miles around on the amazingly flat landscape.

Even if your interest in geology is minimal, there's something about this part of the US that pokes you in the eye and insists you pay attention to geological history. I miss those drives.